The present invention provides novel thermosettable compositions comprising a mixed cyanate of a polyphenol containing a copolymer of an ethylenically unsaturated compound and an alkenylphenyl cyanate, as well as novel hydroxyaromatic oligomers, epoxy resins and advanced epoxy resins thereof.
Preparation of the mixed cyanate of a polyphenol is taught by R. E. Hefner, Jr. in U.S. Pat. No. 4,489,202. In the process, a polyphenol such as 4,4'-isopropylidenediphenol (Bisphenol A) is reacted with less than a stoichiometric equivalent of a cyanogen chloride or bromide in the presence of a suitable base, such as triethylamine. This provides a mixture of monocyanate, dicyanate and, optionally, unreacted polyphenol. Trimerization of this mixture provides hydroxyaromatic oligomers containing the triazine group. The oligomers and unreacted polyphenol, if any, are then epoxidized using methods well known in the art.
Preparation of hydroxyaromatic oligomers containing both triazine and oxazoline groups is taught by R. E. Hefner, Jr. in U.S. Pat. No. 4,487,915. In the process, the mixed cyanate of a polyphenol and an epoxy resin, such as a diglycidyl ether of Bisphenol A, are co-oligomerized. The oligomers and unreacted polyphenol, if any, are then epoxidized using methods well known in the art.
Preparation of advanced epoxy resin compositions containing triazine or both triazine and oxazoline groups is taught by R. E. Hefner, Jr. in application Ser. No. 582,415 filed Feb. 22, 1984, now abandoned. In the process, the hydroxyaromaatic oligomers containing triazine groups or both triazine and oxazoline groups and an epoxy resin, such as the diglycidyl ether of Bisphenol A are reacted in an advancement reaction.
Although each of the aforementioned inventions provide thermosettable resin compositions which, when cured, possess excellent thermal stability and mechanical properties, there is room for additional improvement in the overall mechanical properties, especially tensile strength and elongation. Furthermore, there is substantial room for improvement in the moisture resistance of the aforementioned cured resin compositions. The present invention therefore provides a thermosettable resin which when cured has an improvement in one or more of the properties selected from tensile strength, elongation and moisture resistance.